Vista - DVD-Device goes away every 5 seconds!

I have some Problems with my DVD-Device!
I have XP(Service Pack 2) and Windows Vista Ultimate x64(Service Pack 1) on my PC...
On XP everything works fine but in Vista every 5 seconds my DVD-Device(Sata) goes away and 5 seconds later it is back again! I installed the newest Driver for my DVD-Device but it doesn't work!Of Course I deinstalled my Driver and installed again and of course i restarted my PC so don't ask some questions like that
If you need it :
My PC:
Mainboard: ASROCK 4Core1600Twins-P35
Processor: Intel Core Quad (4x2,4 ghz) Q6600
RAM : 4 gb DDR2 800 (667 mhz)
Graphic : Nvidea Geforce 8600 GT
HD : 250 GB with 2 Partitions (1. Partition XP 2. Partition Vista)
DVD-Device: Don't know the name :P

EDIT:

i have the resolution... installed the false driver... for normal Vista not for 64Bit...